text: Figures shared with 5 live Investigates by the charity RoadPeace reveal a 23% drop in prosecutions in England and Wales in the five years to 2015.
  In the same period the number of convictions fell by nearly 30 per cent.
  The charity blames a reduction in the number of specialist police officers.
  The number of road officers in England and Wales fell by nearly 40 per cent from 7,100 in 2005 to 4,350 in 2014.
  The Department for Transport said: "Britain has some of the safest roads in the world and in 2015 we had the second lowest total of road fatalities on record.
  "We are determined to do more and we've recently announced tougher penalties for those caught using a mobile phone while driving.
  "We have also tightened the law to make it easier to prosecute drink-drivers and drug-drivers."
  Five people die on the UK's roads in the UK every day but campaigners say these incidents are often seen as unfortunate accidents and prosecutions are few and far between.
  John Thompson's 27-year-old son Jake died from head injuries in 2011 after he was hit on a pedestrian crossing in Bristol by a lorry travelling at 38mph in a 30mph zone.
  The family had to fight to persuade Avon and Somerset Police to re-open an investigation into Jake's death after the Crown Prosecution Service said there wasn't enough evidence to bring charges against the driver.
  John is highly critical of the original investigation.
  He said: "We thought straight after the crash there would've been statements taken. It was about a month before the witnesses were interviewed, the phones weren't checked, the interview of the driver didn't take place until about two or three months afterwards and the interview failed to meet the standards which you would expect.
  "There hadn't been a proper investigation. They hadn't followed up on certain key leads like CCTV evidence; they hadn't checked the driver's medical history".
  When the case was eventually taken to court in 2014, it was thrown out, with the judge ruling that there was no case to answer.
  "I felt hurt, disappointed", said John.
  "It was almost as if Jake's life had been lost but there were no consequences as far as the legal system was concerned".
  A spokesman for Avon and Somerset Police said: "After the collision involving Jake we carried out an investigation which, when reviewed, was found to have fallen below standards. Following a complaint raised by Mr and Mrs Thompson we recognised and accepted the need to revisit these matters.
  "As a result, the investigation was re-opened and we renewed our appeal for witnesses, reviewed the information we already had and looked to see if any new lines of enquiry had presented themselves in the interim period. Improvements have since been made in respect of how we approach these types of investigations."
  RoadPeace believes that the declining number of prosecutions for careless and dangerous driving reflects the police's increasing reluctance to investigate fatal collisions.
  "Police are not evaluated on their collision investigation performance. Hence it is not a priority," said Amy Aeron Thomas from RoadPeace.
  "There are no national standards for collision investigation, not even for fatal crashes. Guidance exists but has been weakened in recent years. It is not clear how police evaluate their investigation effectiveness, or if they even do evaluate this."
  The Parliamentary Advisory Council for Transport Safety (PACTS) - a charity which advises MPs on road safety - wants the government to create a UK road collision investigation branch.
  This would be similar to existing organisations which investigate air and rail crashes, and would have the remit of reducing the number of road casualties.
  Steve Barry, an Assistant Chief Constable at Sussex Police and the National Police Chief's Council lead for collision investigations, says he doesn't believe that the reduction in the number of traffic police has impacted on the number of prosecutions and convictions.
  He supports the idea of a national investigation branch but says there is a now a very different approach to road safety.
  "It's less focused on enforcement and prosecution, it's more focused on what is in the public interest, in terms of educating the public, diverting them away from the court.
  "We need to learn how to keep ourselves safe on the roads, as oppose to prosecuting our way into a situation of better safety.
  "The balance is between justice and public interest, or learning, and that's a really difficult balance to explain to a [bereaved] family, but what we have to try and explain is there is a balance between justice, for the victims, justice for the families, at the same time of getting as much evidence, as much learning out of it that informs how we keep other people safe on the roads in future."
  5 live Investigates is on BBC Radio 5 live, 2 April at 11:00 GMT - catch up on BBC iPlayer Radio.
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target: Prosecution and conviction rates for drivers who cause fatal road crashes have fallen sharply - at the same time as police forces have lost thousands of traffic officers.